Module Sequel::Dataset::PreparedStatementMethods
In: lib/sequel/adapters/jdbc.rb
lib/sequel/dataset/prepared_statements.rb

Backbone of the prepared statement support. Grafts bind variable support into datasets by hijacking literal and using placeholders. By default, emulates prepared statements and bind variables by taking the hash of bind variables and directly substituting them into the query, which works on all databases, as it is no different from using the dataset without bind variables.

Methods

Included Modules

Sequel::Dataset::UnnumberedArgumentMapper

Constants

PLACEHOLDER_RE = /\A\$(.*)\z/

Attributes

prepared_args  [RW]  The bind variable hash to use when substituting
prepared_modify_values  [RW]  The argument to supply to insert and update, which may use placeholders specified by prepared_args
prepared_type  [RW]  The type of prepared statement, should be one of :select, :first, :insert, :update, or :delete

Public Instance methods

Sets the prepared_args to the given hash and runs the prepared statement.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 67
67:       def call(hash, &block)
68:         ds = clone
69:         ds.prepared_args = hash
70:         ds.run(&block)
71:       end

Programmer friendly string showing this is a prepared statement, with the prepared SQL it represents (which in general won‘t have substituted variables).

[Source]

     # File lib/sequel/dataset/prepared_statements.rb, line 104
104:       def inspect
105:         "<#{self.class.name}/PreparedStatement #{prepared_sql.inspect}>"
106:       end

Changes the values of symbols if they start with $ and prepared_args is present. If so, they are considered placeholders, and they are substituted using prepared_arg.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 93
93:       def literal_symbol(v)
94:         if match = PLACEHOLDER_RE.match(v.to_s) and @prepared_args
95:           literal(prepared_arg(match[1].to_sym))
96:         else
97:           super
98:         end
99:       end

Returns the SQL for the prepared statement, depending on the type of the statement and the prepared_modify_values.

[Source]

    # File lib/sequel/dataset/prepared_statements.rb, line 75
75:       def prepared_sql
76:         case @prepared_type
77:         when :select, :all
78:           select_sql
79:         when :first
80:           clone(:limit=>1).select_sql
81:         when :insert
82:           insert_sql(@prepared_modify_values)
83:         when :update
84:           update_sql(@prepared_modify_values)
85:         when :delete
86:           delete_sql
87:         end
88:       end

Protected Instance methods

Run the method based on the type of prepared statement, with :select running all to get all of the rows, and the other types running the method with the same name as the type.

[Source]

     # File lib/sequel/dataset/prepared_statements.rb, line 113
113:       def run(&block)
114:         case @prepared_type
115:         when :select, :all
116:           all(&block)
117:         when :first
118:           first
119:         when :insert
120:           insert(@prepared_modify_values)
121:         when :update
122:           update(@prepared_modify_values)
123:         when :delete
124:           delete
125:         end
126:       end

[Validate]